Many varieties of track lighting or rail electrode systems exist. These generally include various designs of spatially separated electrodes that are located parallel to the linear axis of the track. For lighting applications, these “track” or “monorail” systems have at least two continuous parallel electrodes within a mechanical housing, forming a substantially rectangular or prismatic cross-section with continuous electrode contacts along the length of the track. For the purposes of this disclosure, these electrode contact systems are considered to be “axially continuous” contact arrays. That is, a lighting fixture electrical contact remains in an adjacent position to a rail electrical contact as the fixture is translated in a straight line parallel to the axis of the fixed track. Flexible cable type parallel electrode pairs are also another variety of laterally displaced axially continuous rail contact arrays.
Some of these prior art rail are designed to be customized through bending during installation, but are typically difficult to bend in all directions because of their generally rectangular cross section or other asymmetric cross-sectional structure, for example, as shown in representative prior art track cross-sections in FIG. 37 and FIG. 38. The asymmetry of these rails may restrict the ability to practically bend them radially to directions only across the narrow dimension depending upon stiffness. Forming a rail into a closed loop structure may result in undesirable effects from the accumulated difference in path lengths between electrodes on the inside compared to the outside of the bent rail.
While track lighting systems provide more flexibility than stationary lighting fixtures, they do not meet all of the needs for easily configuring the lighting in a space. For example, some fixtures must be disconnected from the rail to reposition them along the rail axis. Also, in order to aim the light output of a lighting fixture attached to prior art electrode systems, additional mechanical knuckle joints, gimbals, or other means are often required to redirect light along different radial directions. These elements increase the weight, size, cost and complexity of the fixtures while still limiting ease of pointing fixtures in space.